The present invention relates generally to an automatic bobbin winder with a plurality of transport loops for bobbins which have partially common transport paths, and more particularly, to an automatic bobbin winder having multiple yarn package preparation devices disposed along the transport paths and an apparatus for coordinating the operation thereof.
A conventional bobbin winder of the general type employed with the present invention is disclosed in U.S. Pat. No. 5,056,725. In addition to a main transport loop, through which most of the bobbins, also known as yarn packages, or cops, are being transported, the transport system of the bobbin winder also includes a separate path by which textile bobbins which are not completely empty are transported from a return path to a feed path.
The bobbin winder includes two yarn package preparation devices for seeking the yarn end and placing it in a predetermined location, accessible by a winder. A first yarn package preparation device is disposed on the separate transport path, which prepares yarn packages for winding by searching for threads on bobbins still containing some yarn. A complete preparation is performed at this preparation device, i.e., after a thread search the thread is deposited at a predetermined location in a manner whereby it can be readily grasped at the winding position and brought to a second yarn package preparation device which is disposed at the feed path and is particularly suited for preparing full cops. First, the start of the thread on these cops is sought in the area of the base of the cop located and loosened, while the main part of this preparation device performs a so-called sheath preparation which involves searching for the thread start on the main wound body. If a cop which was completely prepared in the first preparation device reaches the second preparation device, the thread start can be found neither at the cop base nor on the main wound body, because it has been deposited either in the form of top windings at the tube top or in the tube. The second preparation device can waste time and energy attempting to prepare a cop which was fully prepared at the first preparation device. Therefore, it is desired to have a device or apparatus for determining whether a cop has been prepared successfully at the first preparation device and communicating this information to the control unit for the second preparation device so that operations of the second preparation device can be controlled accordingly.